Oracle Query - help

Why the following code not work -invalid identifier  on documentation_level_desc .

 

SELECT  TO_NUMBER (l.loan_number) AS srvcnum,

         l.product_type_id AS cmdm_Market_Type_num,

        

         (SELECT documentation_level_desc

            FROM CMDMmgr.documentation_level_type d

           WHERE o.documentation_level_id = d.documentation_level_id)

            AS cmdm_doc_type,

           

         (SELECT SPECIAL_FEATURE_CODE

            FROM CMDMmgr.SPECIAL_FEATURE sf

           WHERE TO_NUMBER (lsf.SPECIAL_FEATURE_ID) = sf.SPECIAL_FEATURE_ID)

            AS Harp_CODE

           

    FROM CMDMmgr.loan l

         LEFT JOIN CMDMmgr.loan_origination o

            ON l.loan_number = o.loan_number

         LEFT JOIN CMDMmgr.LOAN_SPECIAL_FEATURE lsf

            ON l.loan_number = lsf.loan_number

   WHERE (product_type_id in (103, 104, 108, 116, 117, 119, 123,

                                                                                    731, 732, 733, 734, 735, 737, 738, 739)

                                                or documentation_level_desc in ('Signature NCO New Value' 'Signature NCO Orig Value')

                                                or SPECIAL_FEATURE_CODE in ('X908' 'T746' 'T786' 'T839' 'T840')

                )